one/include/Quota.h

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/* Copyright 2002-2012, OpenNebula Project Leads (OpenNebula.org)             */
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/* Licensed under the Apache License, Version 2.0 (the "License"); you may    */
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/* http://www.apache.org/licenses/LICENSE-2.0                                 */
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#ifndef QUOTA_H_
#define QUOTA_H_

#include "Template.h"

/**
 *  Base class for resource quotas, it provides basic storage and management of
 *  the quotas. Each resource MUST inherit from it to implement check and 
 *  update methods. Quotas are stored in a template form, each class store the
 *  limits and usage in a resource specific format.
 */
class Quota: public Template
{
public:
    
    /**
     *  Set the quotas. If the quota previously exists its limit is updated.
     *    @param quota_str the quota template in ASCII or XML formats
     *    @param error describe the error in case of error
     *    @return 0 on success -1 otherwise
     */
    int set(vector<VectorAttribute*> * quotas, string& error);

    /**
     *  Check if the resource allocation will exceed the quota limits. If not 
     *  the usage counters are updated
     *    @param tmpl template for the resource
     *    @param error string 
     *    @return true if the operation can be performed
     */
    virtual bool check(Template* tmpl,  string& error) = 0;

    /**
     *  Decrement usage counters when deallocating image
     *    @param tmpl template for the resource
     */
    virtual void del(Template* tmpl) = 0;


protected:

    Quota(const char * quota_name): Template(false, '=', quota_name) {};
    
    virtual ~Quota(){};

    /** 
     *  Sets new limit values for the quota
     *    @param quota to be updated
     *    @param va attribute with the new limits
     *    @return 0 on success or -1 if wrong limits
     */
    virtual int update_limits(VectorAttribute* quota, 
                              const VectorAttribute* va) = 0;

    /**
     *  Creates an empty quota based on the given attribute. The attribute va
     *  contains the limits for the quota.
     *    @param va limits for the new quota if 0 limits will be 0
     *    @return a new attribute representing the quota
     */
    virtual VectorAttribute * new_quota(VectorAttribute* va) = 0;

    /**
     *  Gets a quota identified by its ID.
     *    @param id of the quota
     *    @return a pointer to the quota or 0 if not found
     */
    virtual VectorAttribute * get_quota(const string& id);

    /**
     *  Adds a new quota, it also updates an internal index for fast accessing
     *  the quotas
     *    @param quota is the new quota, allocated in the HEAP
     */
    virtual void add(VectorAttribute * quota);

    /**
     *  Adds a given value to the current quota (vector)
     *    @param attr the quota;
     *    @param va_name name of the quota in the vector attribute
     *    @param num value to add to the current quota;
     */
    void add_to_quota(VectorAttribute * attr, const string& va_name, int num);
};

#endif /*QUOTA_H_*/